Auto insurance market shares remain largely unchanged

While many consumers continue to shop around for the lowest auto insurance quotes, a study by A.M. Best found that the overall market share for auto insurance companies remained relatively stable last year.

According to the report, the largest 25 auto insurance companies in the nation accounted for 82.6 percent of all private policies last year - the same ratio they have maintained during the past three years. Analysts said larger companies continue to have cost advantages due to their size.

"Scale is important in that segment," said A.M. Best analyst Richard Attanasio, vice president in the Property/Casualty Ratings Division. "It's a mature industry."

A.M. Best says State Farm continued to lead the industry with 18.2 percent of the market. Allstate also maintained its second-place spot with 10.4 percent. There were just three changes in the top 10. Nationwide dropped from sixth to eighth, while Liberty Mutual and USAA moved up to sixth and seventh, respectively.

Attanasio added that economic conditions may have affected many policies, as premiums increased just 1.3 percent. He said many families may be looking to reduce their number of vehicles or be dropping comprehensive coverage because they are hanging on to an older vehicle.